I'm in the process of moving my solar setup to a permanent location and have recently upgraded to a Victron MPPT 150/60 solar charger. Currently, I'm using a 12V 280Ah battery, but I'm considering switching to a 24V battery. My main concern is whether the switch is worth it since all my devices (like a freezer, wine cooler, security system, and computer) run on 12V. I've read that a higher voltage could allow me to connect more solar panels to my system, but am I gaining anything if I still need to convert down to 12V for my appliances? Plus, if I do go for the 24V battery, I'm unsure where to place DC-DC converters. Some say between the controller and battery, while others suggest putting them between the batteries and the inverter. Any insight would be greatly appreciated!
3 Answers
Starting with your panels, the Victron 150/60 can handle input up to 150V and outputs up to 60A to the battery depending on the battery voltage. Switching to a 24V setup would allow for double the power transfer from your panels (1440W vs 720W at 12V), but that means your panels have to be capable of providing that much. If everything's currently working smoothly, you might not need to change your system. The DC-DC converter should be placed between your battery and devices, that way it steps down the voltage correctly for your appliances.
If your setup is already well-designed and reliable, I’d suggest sticking with what you have. While moving to a higher voltage might have advantages, it would require major changes to your existing system, which could introduce new points of failure. Just reconfiguring everything and adding buck-boost converters could reduce reliability and efficiency overall. If you're just looking for more capacity, you could consider a new system for additional capacity or repurpose your current one entirely. Also, if you're using 12V panels, wiring them in series could let you achieve a higher voltage without replacing everything, as long as your controller can handle it.
I upgraded from a 12V to a 24V system and use cheap DC-DC converters to power my 12V devices, mainly for LED lights. The main benefit you're looking at is increased efficiency due to lower currents and potentially more solar capacity. If most of your stuff runs from 12V directly, the upgrade may not be justified. If you have or plan to get an inverter, then a 24V model would be more efficient than converting down to 12V first before bumping it up to 110/240V. For connections, consider a bus bar with an automotive fuse box for cleaner and safer wiring.